1. Field of the Invention
This invention relates to a multi-element dental implant for further grafting and anchoring of a dental prosthesis onto an osseous site. The invention includes the component parts of this implant as well as implant dentures made therefrom.
2. Discussion of Background Information
Dental implantology shows an increasing tendency leading to the use of multi-element implants that are composed of two separate elements, with the grafting thereof being successively effected. These multi-element implants are provided with an implantal stump composed of a tubular element which is anchored in the osseous site, and a suprastructure composed of an anchoring shank formed on the implantal stump and of a false stump that serves as a prosthesis base plate. Further, in implants such as the so-called normal implants, the false stump and the anchoring shank have collinear axes; whereas, in implants such as the so-called preangulated implants, the axes form an angle up to 20.degree..
First, the implant stump is anchored by screwing or any other way (DE 1,961,531, EP 0,114,955, or U.S. Pat. No. 3,708,883) in the osseous site, then the suprastructure is attached to the implantal stump by means of the anchoring shank so as to cause the false stump to take a suitable position. Actually, such anchoring in the implantal stump of the shank is achieved by two methods.
In one method the suprastructure shank is composed of a smooth bar, and is permanently sealed within the tubular implantal stump by using a cement. However, in this method, should clinical problems arise, then no removal of the suprastructure will not be possible.
In the other known anchoring method, the suprastructure shank is screwed into the implantal stump through conjugate threading and tapping as provided on these elements (See U.S. Pat. No. 3,589,011). In this method the suprastructure is releasable. However, positioning is inaccurate and hazardous, so much in the longitudinal direction (along the implant axis), because a determination, upon screwing, of the tightening stop limit proves difficult and relates to the orientation of the suprastructure about its axis, which is conditioned upon the final thread position. This angular inaccuracy forms a serious defect impairing preangulated implants, so that suitable positioning can hardly be made using this anchoring method.